Vehicle seat having active head restraint system

ABSTRACT

A vehicle seat assembly having a seatback frame, an upper armature that is movable relative to the seatback frame and a head restraint mounted on the upper armature. A linkage assembly operatively interconnects the upper armature and an impact body such that movement of the impact body relative to the seatback frame acts on the linkage assembly to move the upper armature relative to the seatback frame to cause the head restraint to move toward the occupant. The linkage assembly includes a linkage and a coupler movably connected to the linkage. The coupler includes a first member movably connected to the seatback frame and a second member movably connected to the first member at a location below the upper end of the impact body.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/257,542 filed Oct. 24, 2008, now U.S. Pat. No. 8,162,392 B2, which,in turn, claims the benefit of U.S. patent application Ser. No.10/950,713 filed Sep. 27, 2004, now U.S. Pat. No. 7,644,987, thedisclosures of which are incorporated in their entirety by referenceherein.

TECHNICAL FIELD

The present invention relates, generally, to a vehicle seat, and morespecifically to a vehicle seat having an active head restraint system.

BACKGROUND

Conventional vehicle seat designs of the type commonly found in therelated art typically include a seatback assembly, a lower seatassembly, recliner mechanism, manual or power adjustment mechanism foradjusting a number of positions of either the seatback or lower seatassemblies, as well as a number of safety features including occupantrestraint devices such as seatbelts. The seatback assembly also includesa headrest or head restraint that is typically mounted at the top orupper end of the seatback.

In the context of vehicle seating design, there is an ongoing effort toimprove the safety of the vehicle occupant in the event of a rear endcollision. More specifically, there continues to be an ongoing effort toprovide safety mechanisms that reduce the chance of injury in the regionof the passengers' neck. In the event of a rear end collision, theoccupant is forced against the seat and can experience a large energypulse. In such circumstances, the pelvis, lumbar, and shoulder orthoracic areas of the occupant can exert force on the seatback, andthere is often a separation between the neck and head areas of theoccupant and the head restraint. Depending on the force of the rear endcollision, this separation can be quickly and violently closed bymovement of the upper torso, neck, and head of the passenger toward theseatback in an event commonly known as “whiplash.” Thus, there has beenan ongoing effort to address this problem in the context of vehicleseating safety.

In the past, the head restraint was a relatively static device that wastypically moveable up and down or slightly tiltable, but usually inconnection with adjustments made for the comfort of any given occupantof the seat during normal driving conditions. However, in order toaddress the problems encountered during a rear end collision, dynamic oractive head restraint mechanisms have been proposed in the related art.

For example, U.S. Pat. No. 5,938,279 issued to Schubring et al. andassigned to the assignee of the present invention discloses a dynamicvehicle head restraint assembly that is designed to reduce the amount ofseparation between the occupant and the head restraint in the event of arear end collision. The head restraint assembly includes an impact ortarget plate that is supported by the seatback frame in the general areacorresponding to the thoracic or shoulder region of the occupant. Theimpact plate is pivotally mounted to a linkage that is connected to thehead restraint. In the event of a rear end collision, the force of theoccupant on the target plate actuates the linkage to cause the headrestraint to move toward the head of the occupant, thereby reducing theamount of separation between the occupant and the seatback.

While the dynamic head restraint systems of the type known in therelated art were an improvement over the previously known static headrestraints, there remains a need in the art to better absorb anddissipate the energy generated by the force acting on the seatback inthe event of a rear end collision, especially at the pelvic and lumbarareas, which are generally remote from the head restraint.

U.S. Pat. No. 6,565,150, assigned to the assignee of the presentinvention, discloses a vehicle seat having an active head restraint thatis designed to address this problem. More specifically, the seat has apivotal support assembly that is mounted to the seatback frame and isoperatively connected to the head restraint such that the head restraintmoves toward the occupant in the event of a rear end collision. Thepivotal support assembly includes a lower impact target that is locatedin the pelvic and lumbar regions to dissipate the forces that are firsttranslated to the seatback in this area. The lower target is operativelyconnected to a reaction plate that is pivotally mounted to the seatback.In turn, the head restraint is mounted to the reaction plate.

While the dynamic head restraint systems known in the related art havegenerally worked for their intended purposes and have improved safety,there remains a need in the art for a vehicle seat assembly that moreefficiently and more quickly transfers forces from the occupant to thehead restraint system for more effective actuation of the head restrainttoward the occupant during a collision. There also remains a need in theart for a vehicle seat assembly with an active head restraint systemthat is less expensive, lighter, and easier to assemble.

SUMMARY

In one embodiment, a vehicle seat assembly is provided with a seatbackframe and an active head restraint system operatively supported by theseatback frame. The active head restraint system includes an upperarmature movably mounted to the seatback frame, a head restraint mountedto the upper armature, and a lower armature operatively attached to theupper armature. The lower armature is operable to move toward the upperarmature in response to a predetermined force applied to the lowerarmature and act on the upper armature to move the head restraint towardthe occupant.

In another embodiment, a vehicle seat assembly is provided with aseatback frame, an upper armature is moveable relative to the seatbackframe, and a head restraint mounted on the upper armature. An impactbody is movable relative to the seatback frame and the impact bodyincludes an upper end. A linkage assembly operatively interconnects theupper armature and the impact body such that movement of the impact bodyrelative to the seatback frame acts on the linkage assembly to move theupper armature relative to the seatback frame to cause the headrestraint to move toward the occupant. The linkage assembly includes alinkage and a coupler movably connected to the linkage. The couplerincludes a first member movably connected to the seatback frame and asecond member movably connected to the first member at a location belowthe upper end of the impact body.

In yet another embodiment, a vehicle seat assembly is provided forreceiving an occupant. The seat assembly includes a seatback frame andan active head restraint system operatively supported by the seatbackframe. The active head restraint system includes an upper armaturemovably mounted to the seatback frame, a head restraint mounted to theupper armature and a lower armature movably supported relative to theseatback frame. A coupler extends between the lower armature and theupper armature and operatively interconnects the upper armature and thelower armature such that movement of the lower armature relative to theseatback acts on the coupler to move the upper armature relative to theseatback so as to move the head restraint toward the occupant.

In yet another embodiment, a vehicle seat assembly is provided forreceiving an occupant. The seat assembly includes a seatback frame, anupper armature that is movable relative to the seatback frame, and ahead restraint mounted on the upper armature. An impact body is movablerelative to the seatback frame. A linkage assembly is operativelyassociated with the upper armature and the impact body such thatmovement of the impact body relative to the seatback frame acts on thelinkage assembly to move the upper armature relative to the seatbackframe to thereby cause the head restraint to move upward and forwardtoward the occupant. The linkage assembly includes a linkage movablyconnected to the seatback frame, a first coupler member movablyconnected to the linkage, and a second coupler movably connected to thefirst coupler member and movably connected to the seatback frame.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the invention will be readily appreciated as thesame becomes better understood by reference to the following detaileddescription when considered in connection with the accompanyingdrawings, wherein:

FIG. 1 is an elevational side view of a vehicle seat assembly of thepresent invention illustrated in relation to a schematically shownoccupant of the vehicle seat assembly;

FIG. 2 is a front perspective view of one embodiment of the vehicle seatassembly of the present invention with an active head restraint system;

FIG. 3 is a rear perspective view of the vehicle seat assembly shown inFIG. 2;

FIG. 4 is a side perspective view of the upper end of the vehicle seatassembly shown in FIG. 2; and

FIG. 5 is a side perspective view of the lower end of the vehicle seatassembly shown in FIG. 2.

DETAILED DESCRIPTION

As required, detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely exemplary of the invention that may be embodied in variousand alternative forms. The figures are not necessarily to scale; somefeatures may be exaggerated or minimized to show details of particularcomponents. Therefore, specific structural and functional detailsdisclosed herein are not to be interpreted as limiting, but merely as arepresentative basis for teaching one skilled in the art to variouslyemploy the present invention.

Referring now to the drawings, where like numerals are used to designatelike structure throughout the Figures, a vehicle seat assembly of thepresent invention is generally indicated at 10 in FIG. 1. The vehicleseat assembly 10 includes a seatback, generally indicated at 12, and alower seat assembly, generally indicated at 14, that is supported on aseat track mechanism 16, as is commonly known in the art. The seatback12 may be pivotally connected to the lower seat assembly 14 by means ofa bracket 18 via pivot point 20 that forms a part of the seat trackmechanism 16. In this way, the vehicle seat assembly 10 may be adaptedto recline or adjust in a number of ways that are commonly known in theart. In addition to these common elements, the seat assembly 10 of thepresent invention may include various controls and restraint systems,such as seatbelts, etc. that are not shown, but that are well known inthe art.

An occupant, generally indicated at 24, is shown in phantom seated uponthe vehicle seat assembly 10. The occupant 24 has a pelvic area 26,which is proximate to both the lower seat assembly 14 and to the lowerend of the seatback 12. The occupant 24 also has a lumbar area 28supported above the pelvic area 26, and a shoulder or thoracic area 30supported above the lumbar area 28. Furthermore, the occupant 24 has ahead and neck area 32 supported above the thoracic area 30.

The vehicle seat assembly 10 also includes an active head restraintsystem, generally indicated at 34, operatively supported by the seatback12. The active head restraint system 34 includes a head restraint 36proximate to the head and neck area 32 of the occupant 24. The headrestraint 36 can be positioned in an upright position (shown in solid inFIG. 1) and can be positioned in an operative position (shown in phantomin FIG. 1), wherein the head restraint 36 is pivoted forward and upward,toward the head and neck area 32 of the occupant 24. In the event of arear end collision, the forces that are generated can cause the occupant24 to be driven generally rearward toward the seatback 12. As will bedescribed in greater detail below, forces from the occupant 24 on theseatback 12 are transferred through the active head restraint system 34to ultimately move the head restraint 36 from the upright position tothe operative position toward the head and neck area 32 of the occupant24. This movement of the head restraint 36 better supports the head andneck area 32 of the occupant 24 during the rear end collision, reducingthe likelihood of a whiplash injury.

Referring to FIGS. 2 through 5, the seatback 12 of the vehicle seatassembly 10 is shown in more detail. The vehicle seat assembly 10includes a seatback frame, generally indicated at 38. The seatback frame38 includes a pair of side frame members 40 that are disposed in agenerally vertical orientation and are spaced horizontally relative toone another. The seatback frame 38 also includes upper and lower crossmembers 42, 44, respectively, that extend horizontally between the pairof side frame members 40. As such, the seatback frame 38 defines aforward side 46 and a rearward side 48 of the seatback 12. The seatbackframe 38 may have a “unibody” construction wherein the side framemembers 40 as well as the upper and lower cross member 42, 44 areintegrally formed. In addition, the seatback frame 38 may be assembledfrom separate components making up the side frame members 40 and upperand lower cross members 42, 44 that are then welded or otherwisepermanently fixed to each other. Thus, and from the description thatfollows, those having ordinary skill in the art will appreciate that anumber of different means of operatively interconnecting the componentsof the seatback frame 38 may be employed without departing from thescope of the present invention.

As shown in FIGS. 2 through 5, the active head restraint system 34generally includes an upper armature, generally indicated at 50, and alower armature, generally indicated at 52. The upper armature 50 ismoveably mounted to the seatback frame 38 so as to be disposed proximatethe upper cross member 42 of the seatback frame 38. The head restraint36 is mounted to the upper armature 50 so as to be disposed proximate tothe head and neck area 32 of the occupant 24. Also, the lower armature52 is disposed below and is operatively attached to the upper armature50 so as to be disposed proximate to the pelvic, lumbar, and thoracicareas 26, 28, 30 of the occupant 24. As will be described in greaterdetail below, the lower armature 52 is operable to move toward and actupon the upper armature 50 in response to a predetermined force appliedto the lower armature 52 to move the head restraint 36 toward theoccupant 24. The lower armature 52 is also operable to move toward therearward side 48 of the seatback 12 in response to a predetermined forceapplied to the lower armature 52 and act upon the upper armature 50 tomove the head restraint 36 toward the occupant 24.

As shown in FIG. 2, the lower armature 52 includes a pelvic supportmechanism 54 disposed proximate to the pelvic area 26 of the occupant24, a lumbar support mechanism 56 disposed proximate to the lumbar area28 of the occupant 24, and a thoracic support mechanism 58 disposedproximate to the thoracic area 30 of the occupant 24. In the event of arear end collision, the occupant 24 will exert forces on the lowerarmature 52. If these forces exceed a predetermined level, the lowerarmature 52 transfers the forces to pivot the upper armature 50, therebymoving the head restraint 36 toward the head and neck area 32 of theoccupant 24. Specifically, forces from the pelvic area 26 of theoccupant 24 transfer to the pelvic support mechanism 54, forces from thelumbar area 28 of the occupant 24 transfer to the lumbar supportmechanism 56, and forces from the thoracic area 30 of the occupant 24transfer to the thoracic support mechanism 58. As will be described ingreater detail below, the pelvic, lumbar, and thoracic supportmechanisms 54, 56, 58 cooperatively transfer the forces to pivot theupper armature 50, thereby moving the head restraint 36 toward the headand neck area 32 of the occupant 24. As such, the head and neck area 32of the occupant 24 is better supported during a rear end collision.

One embodiment of the upper armature 50 is illustrated in FIGS. 2through 4. The upper armature 50 includes a cross bar 60 and a pluralityof posts 62. The cross bar 60 is disposed horizontally, and the posts 62are spaced on the cross bar 60 and extend vertically therefrom. The headrestraint 36 is mounted to an upper end of each post 62 such thatmovement of the cross bar 60 coincidentally moves the posts 62 and headrestraint 36. The head restraint 36 can be rigidly mounted to the upperend of the posts 62 or the head restraint 36 could be moveably mountedto the posts 62 in a known manner to allow the head restraint to betilted, raised, and/or lowered relative to the posts 62 withoutdeparting from the scope of the invention.

The upper armature 50 also includes at least one, and preferably, aplurality of linkages 64 shown in FIGS. 2 and 4. In the embodimentshown, there are linkages 64 rigidly mounted to opposite ends of thecross bar 60. The linkages 64 can be rigidly mounted to the cross bar 60in any suitable manner, such as welds, fasteners, or the like. Eachlinkage 64 is also pivotally mounted to the seatback frame 38 at pivotpoint 65. For instance, in the embodiment shown, the seatback frame 38includes a plurality of L-shaped brackets 66, each rigidly mounted toone of the side frame members 40, and each linkage 64 is pivotallyconnected to one of the L-shaped brackets 66. The linkages 64 can beattached to the L-shaped brackets 66 by fasteners, bearings, or thelike. Each of the linkages 64 is also attached to the lower armature 52in a manner to be described, and this attachment allows forces from thelower armature 52 to transfer to the upper armature 50, thereby movingthe head restraint 36 toward the head and neck area 32 of the occupant24.

The vehicle seat assembly 10 further includes at least one, andpreferably, a plurality of biasing members 68 (FIGS. 2 and 4). Eachbiasing member 68 is operatively mounted to one of the linkages 64 andthe seatback frame 38. The biasing member 68 is a coiled extensionspring in the embodiment shown, but the biasing member 68 could be anyother suitable member, such as a torsion spring, without departing fromthe scope of the invention. In the embodiment shown, each linkage 64includes an L-shaped bracket 70. One end of each biasing member 68 ismounted to the bracket 70 through the aperture 72. The opposite end ofeach biasing member 68 is mounted to the side frame member 40. Thebiasing members 68 bias the upper armature 50 toward the uprightposition. Thus, the biasing members 68 provide resistance for the upperarmature 50 from pivoting relative to the seatback frame 38. As will bedescribed in greater detail below, when the lower armature 52 causes thehead restraint 36 to move from the upright position to the operativeposition toward the head and neck area 32 of the occupant 24, thebiasing members 68 return the head restraint 36 back to the uprightposition.

Referring specifically to FIGS. 2 and 3, one embodiment of the lowerarmature 52 is shown. The lower armature 52 includes an impact body,generally indicated at 74. The impact body 74 is generally planar, butcan be of any suitable shape without departing from the scope of theinvention. The impact body 74 is disposed toward the forward side 46 ofthe seatback 12 and is oriented generally vertical. The impact body 74can be made out of any suitable material, and in one preferredembodiment, the impact body 74 is made out of a flexible material suchthat the impact body 74 is comfortable for the occupant 24 to sitagainst. In the embodiment shown, the impact body 74 includes an upperend 76 disposed proximate to the lumbar area 28 and a lower end 78disposed proximate to the pelvic area 26 of the occupant 24. The impactbody 74 is moveable in relation to the seatback frame 38. As will bedescribed in greater detail below, force from the occupant 24 generatedduring a rear end collision is transferred to the upper armature 50 viathe impact body 74.

As stated above, the lower armature 52 includes a lumbar supportmechanism 56 that acts to transfer force from the lumbar area 28 of theoccupant 24 to the upper armature 50. In the embodiment shown, thelumbar support mechanism 56 includes a linkage 80, shown in FIG. 3. Thelinkage 80 is operatively mounted to the impact body 74 such that forcefrom the occupant 24 transfers into the linkage 80. To this end, thelumbar support mechanism 56 further includes a mounting bracket,generally indicated at 82 in FIG. 3. The mounting bracket 82 isoperatively mounted to the impact body 74, and the linkage 80 isoperatively mounted to the mounting bracket 82. More specifically, thelinkage 80 is a bent, rigid rod that is disposed behind the impact body74. The mounting bracket 82 is a bent, elongate sheet that is disposedbetween the linkage 80 and the impact body 74. The linkage 80 defines amiddle section 84, which is straight and extends generally perpendicularto each of the side frame members 40, and two end sections 86, each ofwhich extend from the middle section 84 toward the forward side 46 ofthe vehicle seat assembly 10. The mounting bracket 82 defines a middlesection 88, which is straight and extends generally perpendicular toeach of the side frame members 40, and two end sections 90, each ofwhich are generally U-shaped. The mounting bracket 82 also includes aplurality of attachment members 92, each of which extend from therespective end section 90 and wrap around the middle section 84 of thelinkage 80 as shown in FIG. 3. Preferably, the attachment members 92pivotally mount the linkage 80 to the mounting bracket 82. Furthermore,the mounting bracket 82 is operatively mounted to the impact body 74 ina manner to be described such that forces from the occupant 24 transferthrough the impact body 74, through the mounting bracket 82, through thelinkage 80, and to the upper armature 50, thereby moving the headrestraint 36 toward the head and neck area 32 of the occupant 24.

In one embodiment, the mounting bracket 82 can also be used for mountingother components within the vehicle seat assembly 10. In the embodimentshown, the vehicle seat assembly 10 includes a plurality of motors 94(shown in phantom) that are mounted to the mounting bracket 82. Themotors 94 are operable to adjust the height and curvature of the impactbody 74 for increased comfort of the vehicle seat assembly 10. Thosehaving ordinary skill in the art will appreciate, however, that theimpact body 74 could be nonadjustable suspension system withoutdeparting from the scope of the invention.

Also, as mentioned above, the lower armature 52 includes a thoracicsupport mechanism 58 for transferring force from the thoracic area 30 ofthe occupant 24 to the upper armature 50. In the embodiment shown inFIGS. 2, 3, and 4, the thoracic support mechanism 58 includes acrossbar, generally indicated at 96. The crossbar 96 extendshorizontally between the side frame members 40, and the crossbar 96defines a middle section 98 and two end sections 100. The middle section98 of the crossbar 96 is disposed proximate to the rearward side 48 ofthe seatback 12, and the end sections 100 extend from the middle section98 toward the forward side 46 of the vehicle seat assembly 10 proximateto the side frame members 40. The crossbar 96 can be made from anelongate plate.

In the embodiment shown, the thoracic support mechanism 58 also includesat least one, and preferably, a plurality of enlarged portions 102. Eachof the enlarged portions 102 are generally flat and rectangular and aremounted on one of the end sections 100 of the crossbar 96 by welding orother suitable method. Forces from the occupant 24, especially from thethoracic area 30 of the occupant 24, transfer to the crossbar 96 and tothe upper armature 50 in a manner to be described in greater detailbelow. The enlarged portions 102 have an increased surface area so as toprovide a larger impact area, especially near the shoulders of theoccupant 24.

The lower armature 52 also includes at least one, and preferably, aplurality of couplers, generally indicated at 104 in FIGS. 2, 3, and 4.Each of the couplers 104 is operatively mounted to the upper armature50. At least one of the couplers 104 interconnects the lumbar supportmechanism 56 and the upper armature 50 so as to transfer force from thelumbar support mechanism 56 to the upper armature 50. Likewise, at leastone of the couplers 104 interconnects the thoracic support mechanism 58and the upper armature 50 so as to transfer force from the thoracicsupport mechanism 58 to the upper armature 50. In the embodiment shown,the couplers 104 are common to both the lumbar and thoracic supportmechanisms 56, 58 such that the same couplers 104 interconnect both thelumbar and thoracic support mechanisms 56, 58 to the upper armature 50.However, those having ordinary skill the art will appreciate that acoupler 104 could connect the lumbar support mechanism 56 to the upperarmature 50, and a separate coupler 104 could connect the lumbar supportmechanism 56 to the upper armature 50 without departing from the scopeof the invention. As will be described in greater detail below, thecouplers 104 are operable to move toward the rearward side 48 of theseatback 12 in response to a predetermined force applied to the impactbody 74 and/or the crossbar 96, and in so doing, the couplers 104 act onthe upper armature 50 to move the head restraint 36 toward the occupant24.

In the embodiment shown, the couplers 104 are each disposed adjacent andare generally parallel to respective side frame members 40. The couplers104 each include an upper member 106 and a lower member 108, and each isflat and elongate. The lower member 108 is pivotally mounted to the sideframe member 40 at pivot point 110 (FIG. 2). The upper member 106 ispivotally mounted to the lower member 108 at pivot point 112 (FIG. 2).The upper member 106 is pivotally mounted to the linkage 64 of the upperarmature 50 at coupling point 114 as shown in FIG. 4. The pivotingmovement of pivot points 110, 112 and coupling points 114 is achievedvia fasteners, bearings, or other suitable means.

Each end of the crossbar 96 and each enlarged portion 102 of thethoracic support mechanism 58 are attached via welds or other suitablemeans to one of the upper members 106 of the respective coupler 104.Likewise, the end sections 90 of the linkage 80 of the lumbar supportmechanism 56 are mounted within corresponding apertures 116 in the uppermembers 106 of the respective coupler 104 as shown in FIG. 3. As such,forces transfer from the lumbar and thoracic support mechanisms 56, 58to actuate the couplers 104, thereby pivoting the upper armature 50 aswill be described in greater detail below.

As mentioned above, the lower armature 52 includes a pelvic supportmechanism 54 for transferring force from the pelvic area 26 of theoccupant 24 to the upper armature 50. In the embodiment shown, thepelvic support mechanism 54 includes at least one transfer rod,generally indicated at 118 in FIGS. 2 through 5. The transfer rod 118includes a lower cross bar 120 and at least one, and preferably, aplurality of linking rods 122. The lower cross bar 120 is disposedhorizontally and extends between the two side frame members 40, and thelinking rods 122 are mounted to the cross bar 120 by welding or othersuitable manner and extend vertically therefrom toward the upperarmature 50. The linking rods 122 are spaced horizontally away from eachother. As shown in FIG. 3, the mounting bracket 82 includes a pluralityof mounting members 123, which extend from the middle section 84 of themounting bracket 38 and wrap around one of the linking rods 122 forfixed attachment. The transfer rod 118 is also operatively mounted tothe impact body 74. For instance, in the embodiment shown, the impactbody 74 includes a plurality of apertures 124 through which the linkingrods 122 of the transfer rod 118 extend. One set of apertures 124 isdisposed on the lower end 78 of the impact body 74 as shown in FIG. 5,and another set of apertures 124 is disposed on the upper end 76 of theimpact body 74 as shown in FIGS. 2 and 4. Each linking rod 122 extendsthrough one aperture 124 of each set of apertures 124. The transfer rod118 is also operatively mounted to the upper armature 50. Morespecifically, in the embodiment shown, the upper armature 50 includes aplurality of tabs 126. The tabs 126 are mounted to the crossbar 60 ofthe upper armature 50 and extend toward the forward side 46 of thevehicle seat assembly. The tabs 126 each include an aperture 128, andthe linking rods 122 each extend through one of the apertures 128. Inthe embodiment shown, the tabs 126 include a bushing 129 such that thelinking rods 122 can more easily move within the apertures 128. Also,each of the linking rods 122 includes a bend 130 included proximate andbelow the corresponding tab 126 as shown in FIG. 4. The bend 130 abutsagainst the corresponding tab 126 as the transfer rod 118 moves upward.As will be described, the transfer rod 118 is operable to move towardand act upon the upper armature 50 in response to a predetermined forceapplied to the impact body 74 to move the head restraint 36 toward theoccupant 24.

The vehicle seat assembly 10 further includes at least one, andpreferably, a plurality of ramps 132 as shown in FIG. 5. Each ramp 132is mounted to the lower cross member 44 of the seatback frame 38, behindthe lower end 78 of the impact body 74. Each ramp 132 also includes atleast one cam surface 134 extending generally upward toward the upperarmature 50. In the embodiment shown, each ramp 132 includes a first camsurface 134 a that is in communication with a second cam surface 134 b.The first cam surface 134 a is disposed nearer the lower cross member 44in comparison with the second cam surface 134 b. The first cam surface134 a, extends from the forward side 46 and toward the rearward side 48of the seatback 12 and from the lower cross member 44 toward the upperarmature 50, and the second cam surface 88 b extends upward toward theupper armature 50 and is generally parallel to the side frame members40. Those having ordinary skill in the art will appreciate that the ramp132 can include any number of cam surfaces oriented in any manner towardthe upper armature 50 without departing from the scope of the invention.Both ends of the lower crossbar 120 of the transfer rod 118 are slidablysupported within the ramp 132 on the cam surfaces 134 a, 134 b forguided upward and rearward movement thereon. As such, the lower crossbar120 of the transfer rod 118 moves toward the upper armature 50 on saidcam surfaces 134 a, 134 b in response to a predetermined force appliedto the impact body 74. In the preferred embodiment shown in FIG. 5, thecam surfaces 134 a, 134 b are enclosed by the corresponding ramp 132 toretain the lower crossbar 120 within the ramps 132. The transfer rod 118can include retainers (not shown), such as washers fixed to the lowercrossbar 120, that abut against the ramps 132 to further retain thelower crossbar 120 therein.

In operation of the pelvic support mechanism 54, a rear end collisioncauses the occupant 24 to apply a force to the impact body 74, and theimpact body 74 coincidentally moves toward the rearward side 48 of theseatback 12. This movement causes the impact body 74 to abut against thetransfer rod 118, especially at the lower end 78 of the impact body 74where the linking rods 122 are mounted to the impact body 74. Thisabutment moves the lower crossbar 120 of the transfer rod 118 within theramps 132 on the cam surfaces 134 a, 134 b for guided upward movement ofthe transfer rod 118 toward the upper armature 50. More specifically,the lower crossbar 120 initially moves upward and rearward on the firstcam surface 134 a, and if the impact is sufficient, the lower crossbar120 subsequently moves upward on the second cam surface 134 b. Thismovement causes the bends 130 of the linking rods 122 to abut againstthe tabs 126 of the upper armature 50, thereby pivoting the upperarmature 50 and ultimately moving the head restraint 36 toward the headand neck area 32 of the occupant 24. Those having ordinary skill in theart will appreciate that the ramps 132 and the impact body 74 could bedisposed anywhere in the seatback 12 such that input forces from anyarea of the occupant 24, including the lumbar and thoracic areas 28, 30,could cause the lower armature 52 to move upward toward and act upon theupper armature 50 to thereby move the head restraint 36 to move towardthe occupant 24.

Movement of the impact body 74 also actuates the lumbar supportmechanism 56. More specifically, movement of the impact body 74 movesthe mounting bracket 82 and the linkage 80 toward the rearward side 48of the seat back 12 thereby pulling the couplers 104 toward the rearwardside 48 of the seatback 12. The couplers 104 in turn pull the linkages64 of the upper armature 50 and cause the upper armature 50 to pivotabout the pivot points 65, thereby pivoting the upper armature 50 andultimately moving the head restraint 36 toward the head and neck area 32of the occupant 24.

Additionally, force from the occupant 24 actuates the thoracic supportmechanism 58. More specifically, force from the occupant 24 applied tothe crossbar 96 and enlarged portions 102 causes movement of the coupler104 toward the rearward side 48 of the seatback 12 thereby pivoting theupper armature 50 and ultimately moving the head restraint 36 toward thehead and neck area of the occupant 24.

The biasing members 68 return the upper support armature 50 to theupright position. The biasing members 68 also inhibit the upper armature50 from unnecessarily moving when lower levels of force are applied fromthe occupant 24, such as when the occupant leans back in the vehicleseat assembly 10. Preferably, the stiffness of the biasing members 68 isadjusted such that only forces exceeding a predetermined level willcause the lower armature 52 to actuate the upper armature 50. Thepredetermined level of force is preferably selected based upon theforces involved in an average rear end collision.

Each of the pelvic, lumbar, and thoracic support mechanisms 54, 56, 58act cooperatively to pivot the upper armature 50, thereby causing thehead restraint 36 to move toward the head and neck area 32 of theoccupant 24 for improved support of the head and neck area 32 of theoccupant 24 during a rear end collision. Those having ordinary skill inthe art will appreciate that the kinematics of the vehicle seat assembly10 allows the pelvic, lumbar, and thoracic support mechanisms 54, 56, 58to operate cooperatively. For instance, the coupling points 114 aredisposed relative to the pivot points 65, specifically below andrearward of the pivot points 65, such that generally rearward movementof the couplers 104 cause rotation of the upper armature 50. Likewise,the tabs 126 of the upper armature 50 are disposed forward of thecrossbar 60 and rearward of the pivot points 65 such that generallyupward movement of the transfer rod 118 causes rotation of the upperarmature 50. Also, those having ordinary skill in the art willappreciate that the vehicle seat assembly 10 could include only one ortwo of the pelvic, lumbar, and thoracic support mechanisms 54, 56, 58without departing from the scope of the invention.

In summary, the vehicle seat assembly 10 of the present inventionprovides an active head restraint system 34 that is more responsive toforces that are imparted to the seatback 12 by the occupant 24. Thevehicle seat assembly 10 more efficiently and more quickly transfersforces from the occupant 24 to the head restraint 36 for more effectiveactuation of the head restraint 36 toward the occupant 24, therebybetter supporting the occupant 24 during a rear end collision. Finally,the vehicle seat assembly 10 of the present invention addresses thesespecific problems in a system that is relatively efficient, lightweight,robust, and cost effective.

The invention has been described in an illustrative manner. It is to beunderstood that the terminology which has been used is intended to be inthe nature of words of description rather than of limitation. Manymodifications and variations of the invention are possible in light ofthe above teachings. Therefore, within the scope of the appended claims,the invention may be practiced other than as specifically described.

While exemplary embodiments are described above, it is not intended thatthese embodiments describe all possible forms of the invention. Rather,the words used in the specification are words of description rather thanlimitation, and it is understood that various changes may be madewithout departing from the spirit and scope of the invention.Additionally, the features of various implementing embodiments may becombined to form further embodiments of the invention.

1. A vehicle seat assembly comprising: a seatback frame comprising: apair of side frame members disposed in an upright orientation and spacedhorizontally relative to one another, an upper cross member extendinghorizontally between the pair of side frame members, and a lower crossmember extending horizontally between the pair of side frame members; anactive head restraint system operatively supported by the seatback, theactive head restraint system comprising: an upper armature moveablymounted to the seatback frame and disposed proximate the upper crossmember of the seatback frame, the upper armature comprising: a cross bardisposed horizontally, multiple posts spaced on the cross bar andextending upright therefrom, and a plurality of linkages mounted toopposite ends of the cross bar, each linkage being pivotally mounted tothe seatback frame at a first pivot point, a head restraint mounted toan upper end of each post of the upper armature to be disposed proximateto a head and neck area of an occupant, such that movement of the crossbar consequently moves the posts and the head restraint from an uprightposition toward the head and neck area of the occupant at an operativeposition, and a lower armature disposed below and operatively attachedto the linkages, the lower armature being operable to move rearward, andto act upon the linkages to transfer forces to the upper armature inresponse to a predetermined force from the occupant on the lowerarmature, to move the head restraint toward the head and the neck of theoccupant, the lower armature comprising: an impact body orientedgenerally upright, the impact body including an upper end disposedproximate to a lumbar area of the occupant and a lower end disposedproximate to a pelvic area of the occupant, the impact body beingmoveable in relation to the seatback frame such that force from theoccupant generated during a rear end collision is transferred from theimpact body to the lower armature as the impact body is moved rearward,a lower armature linkage operatively mounted to the impact body capableof transferring force generated during the rear end collision into thelower armature linkage, the lower armature linkage comprising a middlesection disposed behind the impact body and extending generallyperpendicular to each of the side frame members, and two end sections,each end section extending forward from the middle section, and aplurality of couplers interconnecting the lower armature and the upperarmature capable of transferring force from the lower armature to theupper armature, the couplers being operable to move at least partiallyrearward in response to the predetermined force applied to the impactbody to act on the upper armature to move the head restraint toward theoccupant, each coupler disposed adjacent to a respective side framemember, each coupler being pivotally connected to one of the endsections of the lower armature linkage at a second pivot point, eachcoupler comprising: an elongate upper member pivotally mounted to therespective linkage of the upper armature at a third pivot point, and alower member pivotally mounted to the respective side frame member at afourth pivot point, and pivotally mounted to the upper member at a fifthpivot point; and a plurality of biasing members operatively mounted tothe active head restraint system and the seatback frame to bias theupper armature toward the upright position in absence of thepredetermined force.
 2. The vehicle seat assembly of claim 1 wherein thelower armature further comprises a lumbar support mechanism disposedproximate to the lumbar area.
 3. The vehicle seat assembly of claim 1wherein the upper armature is pivotal relative to the seatback frame. 4.The vehicle seat assembly of claim 1 wherein the plurality of biasingmembers comprise a plurality of coiled extension springs; and whereinthe active head restraint system further comprises a pair of L-shapedbrackets, wherein each coiled extension spring is mounted to one of thepair of brackets.
 5. The vehicle seat assembly of claim 1 wherein theimpact body is generally planar.
 6. The vehicle seat assembly of claim 1wherein the impact body is formed from a flexible material for occupantcomfort.